Hi
If you surrender or dispose of your interest in an offshore reporting fund it is treated as a disposal of an asset for the purposes of Capital Gains. Any loss arising within the fund will be a capital loss and can only be set against capital gains on a disposal of an interest in the fund.
More information regarding the computation of offshore income gains and the treatment of the loss can be located at
IFM13550 - Offshore Funds: investors in non-reporting funds: computation of offshore income gain: losses - HMRC internal manual -
GOV.UK (www.gov.uk)
Thank you.